Full knee extension after ACL surgery?

Ok, my answer is going to be in reverse order:

Question 3 - by physio do you mean physical therapist? If so, of course it is ok. You need to work with a physical therapist who is going to work with you and make you feel comfortable with the plan that the two of you have laid out. If you're doubting the process and you think you need better explanation, then you should ask for one from your current therapist. However, if the problem is based on his/her approach and it not meshing with yours, don't be afraid to ask your doctor for a referral.

Questions 2 and 1- I found this article to be helpful. I think the writer makes a nice case for a sort of midway point between your fear and what most people sort of expect. Yes, ideally your level of extension would be the same for both knees. But you can achieve that even after one month post-surgery. Consult your doctor and a new physical therapist (if you want that). They should be able to discuss methods for increasing flexibility. If you want to be pushed harder, make sure that your doctor gives you the ok because only your doctor knows your knee best.

I hope this helped, good luck!